The invention relates to a base for holding the plaster of paris model of a set of teeth in the preparation of dentures, the base including a bottom to which is attached an upright, circumferential exterior wall adapted to the shape of the jaw, with guide elements, for the plaster of paris model that can be sawed apart, projecting perpendicularly from the bottom.
The provided base is used in the production of dentures of any type, such as crowns, inserts, bridges and dental prostheses made of plastic, ceramics and metals.
Various embodiments of bases for holding the plaster of paris set of a patient's teeth made from a silicone rubber impression are already known. In the production of extensive dental prostheses, a model must be made of the teeth of the maxilla and of the mandible so that the proper interaction of the prosthesis with the existing teeth can be ensured. For this purpose, plaster of paris models of both jaws are inserted into an articulator--which simulates jaw movement--to thus constantly check the height and configuration of the chewing surfaces in the dental laboratory.
A horseshoe-shaped bar is known for fastening a plaster of paris model to a base provided with a bottom and an exterior wall, with such bar being disposed as a guide element on the base. However, this bar permits neither easy removal of the plaster of paris model or its parts from the base nor does it permit the precise, unmistakable repositioning of the removed parts (DE-OS 3,505,680). The use of a zigzag bar on the bottom also does not ensure accurate, unambiguous repositioning of the plaster of paris parts (DE-OS 3,521,137).
Also known is a base plate which includes a plurality of bores into which cylindrical or out-of-round guide elements can be pressed entirely as required. However, the manufacture of such a base is rather expensive, it can be employed only together with a correspondingly configured direction-finding plate and its manipulation is rather complicated. Since the guide elements are configured and provided to remain in the plaster of paris model or its parts, problems arise if a ceramic casting mass is employed which must be fired in a kiln. (DE-OS 3,436,094).